Wrist protector



Nov. 6,1945. M. JUNGMANN WRIST PROTECTOR Filed Aug. 5,1943

2 Sheets-Sheet 1- INVENTOR.

'Marfih Dogma/m v M, ATTORNEY Nov. 6, 1945. M. JUNGMANN WRIST PROTECTORFiled Aug. 5 194:5 I 2 Sheets-Sheet 2' IN BVTOR. Mqrf/n Jim ATTORNEYPatented Nov. 6, 1945 UNITED STATES PATENT OFFICE V 2,388,330 s I WRISTPROTECTOR Martin Junginann, New York, N. Y. Application August 5, 1943,Serial N... 497,478

3 Claims.

This invention relates to a device for protecting and/ or supporting thewrist and hand and/ or elements thereof.

The construction of the human hand enables the individual to perform amultitude of manipulations in a great variety. This is made possible bythe enormous number of combinations in which the elements forming thehand e. g. bones, ligaments, capsules, and muscles, may be brought intoaction for each single task. The efficient action of the handdependsupon the correctly balanced interplay of these elements, whichexert adequate strength from within, or counterbalance and withstandforces acting upon the hand from without. As long as the forces actingwithin the hand and those acting from without are balanced within thelimits determined by physiological limitations of the muscles and by thestructural resistance of the levers and their junctions, the conditionswill be normal and will not cause harm or damage to the organ. It isonly when said limits are exceeded as a consequence of undue strain,that the symptoms" of overstrain and fatigue occur.

As muscles and nerves have only a limited working capacity and aresubject tofatigue, the

equilibrium in the interplay of muscles, and the condition of their toneis easily disturbed. This is often the case, as many of the tasks forwhich.

the hand is used, are to be performed over a relatively long period oftime, and, therefore tiring. Furthermore, there are many manipulations,in which one single muscle-group is unduly strained unilaterally. As aconsequence, the correct. leverage may be lost, and the workingconditions for all groups of muscles may be changed unfavorably. In suchcases, one muscle-group will develop more traction than its counterpart,and cause deviation of the lever more and more toward one side. In thecourse of progressive fatigue, the tone of the muscle will increase, andthereby the muscle become shorter than it was or normally should be.Hand in hand with this one-sided active contraction, goes a passiveoverstretching and overextension of the muscles on the opposite side ofthe lever, accompanied by an increase in their length.

In addition to this kind of pathogemc phenomena, there are other causesresulting in. disturbances and damages of the hand,

Primarily the human hand is built for use in traction whereby pull isexerted in the direction from the elbow toward the fingers or in theopposite direction. This means that the main forces act along thelongitudinal axis of theforearm and the hand, with no or little rotaryor torsional moments brought into action. However, in many cases handsare used in such a mannerthat rotary moments and torsions have to beproduced or counteracted. This kind of action is particularly tiring forthe muscles which give in, and cannot stop the spraining of the jointswithinthe wrist.

Another kind of damage may be caused by the necessity of using the handfor supporting weights or for pushing heavy loadsor for absorbingshocks. In these cases, the forces acting along the longitudinal axis ofthe forearm, have a compressing and jamming effect upon the wrist partswhich are squeezed in, compressed and often displaced out of the properalignment.

One of the efiects of overfatigue of the muscle is the loss of therelaxing ability, and, therefore, lack of rest and recovery when not inuse. An overtired and overexcited muscle remains in hypertonic, cramped,spastic condition, and develops tensions, which usually last for a longtime, and hold the tissues of the joints under abnormal, harmfulpressure. This state of reflex-hypertonus is an intermediary stage whichoccurs before an actual deviation of the joint from its middle positiontakes place. Such shifting of the joint out of its balance occurs whenthe protectingmechanism against, overstretching of the muscles breaksdown, as a consequence of continued abuse of the hand in spite ofsymptoms of overfatigue. The symptoms in this phase may be p v ness,weakness, clumsiness, unreliability, and, at times, even the sense ofparalysis. These symptoms are accompanied by objective signs, such ascongestion, swellings, exudation, inflammatory reactions, tenderness ontouching, rigidity, etc. In a later phase of this condition, changes inthe range of excursions in the joint, and deviations from the normalposition are found, accompanied by changes in the shape of the hand andin the consistency of the tissues. In the course of such development,the unbalanced hand may be affected in various ways on ligaments andcartilage.

such as sprains, strains, lesions of ligaments and joints, which oftenmay result inso-called arthritic or -arthrotic conditions. Under theseconditions, undue pull, and transmitted jogs and jolts, affect theinsertions of the muscles on the arm to the hand and fingers.

bones. The periosteal tissues then often become irritated and inflamedand produce periosteal reactions, such as pain, swelling, inhibition ofmotion, etc.

Owing to the fact that the muscles of the hand proper overlap not onlythe wrist-joints but also the elbow joints and insert partly even on thehumerus (upper arm bone), primary disturbances of the wrist may manifestthemselves in the elbow region. Upon progressive fatigue and forcedcontinued use of the hand, the organism tries to compensate for theinsufficiency of primary muscles, by bringing into play a suitable groupof muscles in the adjoining region, i. e. the elbow and upper-arm. Thus,as a consequence of pathological fatigue and unbalance originallypresent within the wrist, pathological effects may manifest themselvesin the elbow-, shoulder-, and even neck-region.

The above described pathology requires the provision of proper care. Inmany cases, however, circumstances do not allow proper care andsufiicient rest for the recovery of the affected organ. As a rule,workers cannot afford to stop their work for a, longer period of time,and they cannot work with their hand in protective casts or splints.

For this reason, various attempts have been made to protect the wrist bymeans of straps or cufis which. are adapted to tighten the wrist firmlyand fix the joint by constriction. The known devices of this type may beof use under special circumstances, 1. e. during heavy work, in spite ofthe fact that they cause considerable tightening of the tendon sheetsrunning from the fore- This interferes, of course, with the finer actionof the muscles and the blood circulation, as it necessarily ties up thefree flow of blood, at least in the venous part. Such effects make theuse of the usual wristcuifs inconvenient and harmful.

The main object of the present invention is to provide a device adaptedto protect the hand fromundue strain without interfering with thenatural functions of the elements included in or forming the hand.

Another object ofthis invention is to provide a device adapted to limitthe excursion of the wrist-joints to a sufficient extent for protection.

It is also an object of this invention to provide a device which isadapted to guide the movements of the hand within a reduced range bytracks of adequate design and dimensions in order to enable the hand tomove without marked interference of action and without constriction.

A further object of my invention consists in providing a device which isadapted to serve as a support for the hand while not in use, so as toinduce the hand to relax by allowing the hand to lean against a firmsupporting element. Other objects and the advantages of the inventionwill appear from the following specification and claims, and theappended drawings.

The wrist-protecting device according to my present invention consistsof a cuff-like body consisting of a suitable unextensible material, forexample leather, plastics, fibrous materials and fibrous compositions,said body being formed or molded in such a manner and dimensions as toaccommodate the wrist. It is adapted to cover the back of the hand up tosome distance, preferably A1"- from the distal knuckles of themetacarpals, and bends and turns around the metacarpal bones of thethumb and the fifth finger, respectively. On the palm of the hand itmust accommodate and fit the ball of the thumb, and the ball of thefifth finger. The material forming the device is relatively rigid andunyielding in the direction of the longitudinal axis of the device, butsufiiciently flexible around said axis in directions transverselythereto.

A preferred embodiment of the invention is shown by way of example inthe appended drawings which form a part of this specification, and inwhich Fig. 1 is a plan view of the palm of a left hand provided with aprotecting device according to my present invention;

Fig. 2 is a back view of the hand and the device shown in Fig. 1;

Fig. 3 is a diagrammatic dorsal view of a left hand indicating the bonesystem of the hand, and the wrist-protector applied thereto, while Fig.4 is a diagrammatical, planar view of a left hand;

Fig. 5 shows a diagrammatical cross-sectional view of a hand and theprotector applied thereto.

Referring now to the drawings, 1 is the protecting device covering theback of the hand up -to some distance from the distal knuckles 2 of themetacarpals, as best shown in Fig. 3. As best shown in Fig. 5, thedevice bends and turns around the metacarpal bones, 3, 3' of the thumb,and the fifth finger, respectively. On the palm of the hand itaccommodates and fits the ball 4 of the thumb and the ball 5 of thefifth finger.

The device is closed on the dorsal plane of the hand, as shown in Fig.2, but is open on the volar side, as shown in Fig. 1. The edges 6, 6 runapproximately paralle1 to each other along the wrist and the forearm,and then turn in a smooth curve I, l to the back of the forearm.

The wrist protector covers the forearm up to about one inch above theknuckle 8 of the ulna,

and the dorsal plane 9 of the device is so molded that it canaccommodate said knuckle of the ulna in an adequate cavity.

The profiles of my wrist-protector are so shaped that they are adaptedto give freedom of action to the wrist as the pivot in all directions toabout of the physiological range of excursion. An elastic strap I0 isprovided on the volar side of the wrist in the height of the knuckle ofthe ulna. This elastic strap, which can be tightened or loosened, f. e.by means of a buckle l l, and fastened by means of clasp l2 and button I3, serves for joining together the end portions l and l" of the device,and. for putting on and removing the device. The device is held in itsproper place by means of an unelastic oblique strap l4, running from thedorsal side of the space between the thumb and index finger to the ballof the fifth finger on the palmar side. Strap l4 may be made adjustablein length. I prefer to make this strap or lace rather narrow and of asoft and pliable material so that it does not disturb the use of thehand.

If desired, elastic steelsprings H can be fixed and pivoted to the loweredge I5 of the device, and fastened to the finger by means of loop it ofleather or another material. This additional element, which serves forthe particular guidance of a single finger or several fingers, may be ofspecial use for the thumb, the basal joints of which are particularlyunstable. Owing to its very frequent exposure to extraordinar strain andunfavorable mechanical exertion, the thumb is affected most frequently,and, therefore, needs increased protection.

The wristprotector according to my present invention does not constrictor tighten th wrist, but

gives freedom of action and movement within 90 of the physiologicalexcursion. The excursions of the hand are checked in the followingmanner:

Due to the shape and the material of the device which yields to fiexionaround the longitudinal axis, it is sufficiently rigid and unyielding inany other direction. In dorsal flexion of the wrist it takes up thepressure of the flexed metacarpal bones, and transmits it to the bonesof the forearm whereby the movement of the hand is stopped by the firmresistance of said bones on both ends of the device, and the deviceitself. A similar procedure takes place in the lateral defiexions of thehand, i. e. the radial or ulnar abduction, respectively, where themetacarpal bone of the thumb is checked by the radius due to theresistance of the device, whereas in the ulnar deviation the pressure ofthe fifth metacarpal bone is taken up by the ulna. The defiexion towardthe palmar plane is stopped on the fifth metacarpal bone in a similarmanner, and transmitted to the ulna. In addition to this, the increasedtension of the elastic strap on the palmar side of the wrist, preventsopening of the device and hampers further fiexion on the radial sidewhich is combined with ulnar abduction. The torsion around thelongitudinal axis is arrested partly by adhesion and friction of thewell fitting walls of the device and the hand, and also by fixation bystrap [4.

The firmness in various directions of my wristprotector can beincreased, if desired, by the incorporation of tempered and adequatelyshaped steel bands or equivalent means.

My wrist-protector may be used in different ways, depending upon theparticular need of the individual. It may be worn during strenuous workas a protection against undue stress, or as a resting bed worn for hoursor continuously, for conditioning and facilitating relaxation of themuscles before or after work. Furthermore, the

device may be worn in order to guard a weak and unbalanced wrist afterinjury, assisting the medical after-care when casts or splinting are notnecessary. As a means of prevention, the device may be employed to avoidoverstrain of the hand by certain types of work, such as typing, workwith riveting tools or machines, etc.

Experience has shown that in proper use of the device a damaging effectnever occurs. As the effects of a primary disturbance in the region ofthe wrist may spread and affect the whole functional unit of the upperextremity, the use of my wrist-protector is also useful in cases whereelbow, shoulder or neck-region are afiected secondarily.

It is to be understood that my invention is not limited to the specificembodiments presented herein for illustration, and is susceptible ofvarious modifications within the scope and spirit of the invention asdefined in th appended claims.

I claim:

1. A wrist-protector consisting of a cuff-like body of an unextensiblematerial yielding to flexion around its longitudinal axis but onlyslightly yielding in other directions, said body being adapted toaccommodate the wrist, and

form a continuous cover on the back of the hand,

said cover slightly extending beyond the knuckle of the ulna, while itslower edge is spaced AW-V from the distal knuckles of th metacarpals,said body bending and turning around the metacarpal bones of the thumb,and the fifth finger, respectively, and accommodating the ball of thethumb and the ball of the fifth finger on the palm of the hand, beingopen on the volar side of the hand, said body being provided with anunelastic holding strapprovided in the space between the thumb and indexfinger, and with an elastic strap for joining together spaced endportions of the wrist-protector on the volar side of the hand.

2. A wrist-protector consisting of a cuff-like body of an unextensiblematerial yielding to fiexion around its longitudinal axis, butonlyslightly yielding in other directions, said body being adapted toaccommodate the wrist, and form a continuous cover on the back of thehand, said cover slightly extending beyond the knuckle of the ulna,while its lower edge is spaced from the distal knuckles of themetacarpals, opposite end portions of the body being spaced and adaptedto be joined on the volar side of the hand, the wrist-protector beingprovided with at least one steel spring fastened and pivoted on itslower dorsal edge, said steel spring being adapted to accommodate andprotect a finger.

3. A wrist-protector consisting of a cuff-like body of an unextensiblematerial yielding to fiexion around its longitudinal axis, but onlyslightly yielding in any other direction, said body being adapted toaccommodate the wrist, and

- form a continuous cover on the back of the hand,

said cover slightly extending beyond the knuckle of the ulna, while itslower edge leaves free the distal knuckles of the "metacarpals, oppositeend portions of the body being spaced and adapted to be joined on thevolar side of the hand, said body being provided with means for holdingit in place, said means running from the dorsal side of the spacebetween the thumb and index finger to the ball of the fifth finger onthe palmar side, and with means for connecting spaced end portions ofthe body on the volar side of the hand, said wrist-protector beingadapted to guide and protect the elements of the hand withoutinterfering with the natural functions of said elementls.

MARTIN J UNGMANN.

